Hydraulic ship&#39;s armor



P. J. VAN POELVOORDE.

HYDRAULIC SHIPS ARMOR, APPLICATION HLED NOV. 14. 19M.

: 375,335 Patented Apr. 19, 1921'.

UNITED STATES PATENT OFFICE.

PIETEB JACOBUS VAN POELVOORDE, OF WELTEVREDEN, BATAVIA, DUTCH EAST INDIES.

HYDRAULIC SHIPS ARMOR.

Specification of Letters Patent. P t t d A 19, 1921 Application filed November 14, 1919. Serial No. 338,061. 0

To all whom it may concern:

Be it known that I, PIETER J. VAN Pom.- voonnn, a subject of the Queen of the Netherlands, and a resident oi lVeltevreden, Batavia, Dutch East Indies, have made certain new and useful Improvements in Hydraulic Ships Armor, of which the following is a specification.

My present invention relates generally to the armor construction of ships, and more particularly to means whereby to supply the existing lack of adequate protection of ships against under water attack and the principal object of my invention is to provide a ship construction including an effective armor against the explosive action of torpedoes and mines.

A further and more specific object of the invention is the provision of a protective construction which will embody the presence of a water mass maintained between inner and outer walls, whose relation is such that an explosion against the outer wall will have its destructive efi'ect dissipated in this water mass. In order to do this it is obvious that the outer wall must have movement relative to the inner wall, otherwise the effect of the explosion would be simply transmitted directly from one to the other through the connections therebetween, and it is further necessary that in this relative movement between the walls the space therebetween in which the water mass is held must have an outlet through which a portion of the water mass may find its way as the area of the space is reduced upon inward movement of the outer wall. as mentioned.

In the accompanying drawing I have illustrated a construction capable of carrying out my present invention although I do not wish to be understood as limiting myself to the details illustrated.

In this drawing Figure 1 is a transverse vertical section through one side portion of a ship constructed in accordance with my invention, the line X X indicating the vertical axis of the cross-section, and Fig. 2 is a diagrammatic plan view of a ship showing the application of my invention thereto.

Referring now to these figures, I have shown a ship as including in its construction an outer wall A and an inner wall B, in spaced apart relation, to provide for the maintenance of a water mass M in the space between the walls. In the illustration C is the bottom of the ship or vessel whose outer frame F supports the outer wall A, the ship having an inner frame F which supports the inner wall B and which is connected to the outer wall and the outer frame R, at the point D adjacent to the base C. This leaves the upper portion of the inner wall B entirely free from the outer wall, so that it is capable of some yielding movement with respect to the outer wall, which may be taken up and dissipated in the water mass M owing to the upwardly opening water chambers. I

It is known at the present time that water is capable of transmitting pressure with a speed of 1400 meters per second calculated by Newton and measured by Colladon and Strum in the year 1827. When for in stance a torpedo explodes against the outer wall A upon contact therewithpressure is generated against wall A and, through this wall, upon the water mass M which, with a torpedo having a charge of for instance 100 kilograms of gun cotton, measures in speed approximately 7,000 meters per second. As the speed of the explosive force against the water mass is thus approximately five times, or several times at least, the speed at which the water mass M is ca pable of transmitting pressure, it is obvious that transmission of the explosive force through the water mass will fail and the effect of the explosion'absorbed and dissipated in the compression of the water layers surrounding the immediate locality of the explosion.

It is obvious, therefore, that the pressure of the explosion will be proportionately decreased as the distance is increased between the exploding substance and the part or parts, which it is desired to protect against the effect thereof.

Tests carried out along the above lines have shown that the explosive pressure decreases from 1000 to 80 kilograms per square centimeter along distances varying between zero and one meter, and it is obvious therefore, that the decrease in the explosive pres-- sure through the water mass is effectively sudden.

Of course in practice the water mass M must be provided with such width as will prove necessary to reduce the pressure at the inner wall B below danger point and it must have an outlet permitting it to freely expand or overflow upon relatively greater movement-of the wall' A than the wall B owing to the relatively greater pressure at the time of-explosion against the outer wall.

Exhausting and dissipation of the effect of explosion in water has already been proved and adopted in the application of the well known torpedo net where a'water mass is present between the net and the hull of the vesselwhich the net surrounds.

My present invention improves the action, and at the same time avoids certain disadvantages in the use of a net, the effective use of which is limited to the time or times "when the ship is without headway. As soon in motion the net is usually raised and there 7 is at thistime no protective action.

. any and all times.

My invention, however, provides for'the permanent use'of a protecting water mass which is present and ready to function at Being impervious, the outer wall A of the ship as I propose to construct it, will avoid all of the tremendous resistance incident to a torpedo net and will simply act against the water in place of the usual single wall of the ship.

The'above-mentioned outlet through which a portion of the watermass M may find its wayas the area of the space is reduced, is

formed by leaving the upper part of the Wall E open between O O in Fig. 1.

As a practical direction for carrying my invention into effect, but standing without any relation to the real suggestion of this invention, maybe mentloned the provision Fig; Zbetween and perpendicular to both walls A and B, which cross-bulkheads subdivide the space between both walls into smallerparts or chambers H, in order to.

prevent or at least to reduce the push of the ,moving water mass M between both walls when the ship, is pitching. f

p I am aware that it has been previously proposed'to utilize a water-mass between inner and outer walls which are formed as a structural entirety but where the explosive pressure is obviously transmitted more or 'lGSS ClII'GCtly through the wall connections and there isno exhausting of theexplosive force in the water mass as provided "for in my present invention.

'I claim: v a A ship having outer and inner walls of which the outer wall is the usual wall of the vessel and the inner wall extends from the bottom of the ship in spaced apart relation to the outer wall and with its upper edge open, whereby to form with the outer wall an upwardly opening chamber for the reception of awater mass. 7

V PIETER JACOBUS van POELVOORDE.

of cross-bulkheads E in horizontal view in I 

